data/examples/java/regex_9.java
import java.util.regex.Pattern;
import java.util.regex.Matcher;

class Regex9 {
    static final Pattern ROUTE_PATTERN = Pattern.compile("([&!=,]*)\\s*([^&!=,\\s]+)");

    private static Map<String, MatchPair> parseRule(String rule)
            throws ParseException {
        Map<String, MatchPair> condition = new HashMap<String, MatchPair>();
        if (StringUtils.isBlank(rule)) {
            return condition;
        }
        // Key-Value pair, stores both match and mismatch conditions
        MatchPair pair = null;
        // Multiple values
        Set<String> values = null;
        final Matcher matcher = ROUTE_PATTERN.matcher(rule);
        new Here().given(ROUTE_PATTERN, Pattern.compile("([&!=,]*)\\s*([^&!=,\\s]+)")).given(rule, "&abc").checkTrue(matcher.find()).checkEq(matcher.group(1), "&").checkEq(matcher.group(2), "abc");
        while (matcher.find()) { // Try to match one by one
            String separator = matcher.group(1);
            String content = matcher.group(2);
            // Start part of the condition expression.
            if (StringUtils.isEmpty(separator)) {
                pair = new MatchPair();
                condition.put(content, pair);
            }
            // The KV part of the condition expression
            else if ("&".equals(separator)) {
                if (condition.get(content) == null) {
                    pair = new MatchPair();
                    condition.put(content, pair);
                } else {
                    pair = condition.get(content);
                }
            }
            // The Value in the KV part.
            else if ("=".equals(separator)) {
                if (pair == null) {
                    throw new ParseException("Illegal route rule \""
                            + rule + "\", The error char '" + separator
                            + "' at index " + matcher.start() + " before \""
                            + content + "\".", matcher.start());
                }

                values = pair.matches;
                values.add(content);
            }
            // The Value in the KV part.
            else if ("!=".equals(separator)) {
                if (pair == null) {
                    throw new ParseException("Illegal route rule \""
                            + rule + "\", The error char '" + separator
                            + "' at index " + matcher.start() + " before \""
                            + content + "\".", matcher.start());
                }

                values = pair.mismatches;
                values.add(content);
            }
            // The Value in the KV part, if Value have more than one items.
            else if (",".equals(separator)) { // Should be separated by ','
                if (values == null || values.isEmpty()) {
                    throw new ParseException("Illegal route rule \""
                            + rule + "\", The error char '" + separator
                            + "' at index " + matcher.start() + " before \""
                            + content + "\".", matcher.start());
                }
                values.add(content);
            } else {
                throw new ParseException("Illegal route rule \"" + rule
                        + "\", The error char '" + separator + "' at index "
                        + matcher.start() + " before \"" + content + "\".", matcher.start());
            }
        }
        return condition;
    }
}
